The initial editing of points and generation of contours has been no problem but, now I find myself with a large topography (2000+ pts) and, after thinking that the drawing was finished, I find that certain points need to be removed from the DTM and others need to be added. I'm not finding in the help files a description of this particular process. I'm sure that in the near future I will return to the project and collect more points to be added to the drawing. My concern is the contour lines that have already been written to the .DWG. After I edit the points to be added and/or removed (and maybe draw more break lines) I suppose that I will extract all points and break lines over again.This will create a new .TIN and then create new contours. Will this remove the old contours and create new ones? Now, when I go back out and locate new points beside the area that we have already topo(ed) can I add points to existing DTM (my preference, I think) or create a new surface and edit the contour lines so that they match exactly? I do not smoothe the contours for final map so labeling shouldn't be too bad. Thank you

Adding and removing points from a DTM will not affect any contours you have allready drawn. They are not interactive.You can delete the contours or just draw new ones on a new layer. It would be a tedious job editing contours.

If you use Coordinate editor you can add or remove points from the DTM inside that set of menus presented.EDIT, add selection to DTM at bottom of that menuAny change to the DTM in this way strips ALL breaklines which is a pain so you will need to redo all the breaks again.

Personally I always keep the old surfaces and create new ones from scratch if needed or just by saving existing ones to another name and then editing those.